Bending brake



Patented Nov. 24', 1942 BENDING BRAKE John Jensen, Rockford, 111.,assignor to Whitney Metal Tool Company, Rockford, 111., a corporation ofIllinois Application July 13, 194.0,- Serial'No; 34.5.2247;

2 Claims.

The invention relates to sheet metal bending brakes generally and isconcerned more particularly with an improved platen structure for use insuch brakes.

One object of the invention is to provide an improved platen structurefor brakes of the above general character which materially increasestheir range of utility by adapting them for the performance of a widervariety of operations than has heretofore been practicable.

Another object is to provide a general purpose brake of simple,inexpensive construction particularly suitable for transportation fromone job to another and which is capable of performing all of theoperations usually encountered under such conditions, the brake alsobeing suitable for small shops or the like which require facilities fornumerous sheet metal bending and forming operations but where the volumeof work is insufficient to warrant the installation of separate machinessuch as have heretofore been used for the different operations.

' Still another object is to provide a sectional platen structure forbending brakes embodying one section capable of operating on sheets ofheavier gauge than can ordinarily be handled by finger equipped boxbrakes and another section equipped with fingers for box bending wherebyeither type of work may be performed without requiring changes in oradjustment of z the brake.

Other objects and advantages of the invention .will become apparent fromthe following detailed description of the preferred embodimentillustrated in the accompanying drawing in which:

Figure 1 is a fragmentary perspective view of a bending brake platen andcooperating elements embodying the features of the invention.

Fig. 2 is a vertical sectional view showing details of the bed, platen,apron, and other elements of the brake. v

Figs. 3 to 6, inclusive, are digrammatic views showing a number ofdifferent set-ups for enabling the brake to perform various types of operations.

By way of illustration, the invention has been shown and will bedescribed herein as embodied in a bending brake of the general typeshown in the Jensen Patent No. 2,028,869 granted J anuary 28, 1936. Itwill be understood, however, that the invention may be readily appliedto other types of bending brakes. It will also be understood thatvarious changes in the form, construction and arrangement of the partsmay parting from the spirit and scope of;the invention as expressed inthe appended claims.

. Referring now to the drawing, the brake selected to illustrate theinvention comprises the usual frame including upright end members iiibetween which is fixedly supported a platen I l of novel andadvantageous construction adapted .to cooperate with a bed l2 inclamping a metal sheet in place for a bending operation and to define abending edge of variable length for the sheet. In the exemplary machine,the sheet to be operated on is supported by and clamped against theunder side of the platen by the bed 12 which is disposed below theplaten and uided for movement toward and from the same. The bed asherein shown comprises a rigid I beam l3 bolted or otherwise suitablysecured at its ends to box-like brackets M (Fig, .2) slidable on theframe members It. A bed plate It is removably attached to the top of theI-beam so as to project forwardly therefrom. This plate constitutes theportion of the bed which cooperates with the platen to clamp the sheetin place during the bending operation.

Movement of the bed to and from clamping position may be efiected in anypreferred man ner as by separate actuating mechanisms, similar to thosedisclosed in the above mentioned pat ent, associated with each end ofthe bed structure. One such mechanism is shown in Fig. 2 and comprises ahand lever I6 pivoted at one end on a head block I! rigid with the framemember In. This lever is connected by a link It with the head guidingbracket M, the link being arranged to shift-to an over-center positionfor holdingthe bed in its raised or clamping position. To facilitate itsmovement, the bed is desirably counterbalanced by a coiled compressionspring l9 acting on the under side of each of the brackets l4.

Forbending a sheet clamped between the bed and platen, a swinging apron20 is hingedly connected to the bed [2; The apron in its preferred formcomprises a normally depending leaf 2| supported with its upper edge inthe same plane as the upper surface of the bed plate I5 and as closelyadjacent the front edge of the plate as is practicable. The upper edgeof the leaf thus constitutes the active or bending surface of the apron.Toadapt the brake for making reverse bends spaced apart a distance lessthan the overall thickness of. the leaf 2|, the bending surface 7 isformed in part by a removable strip 22 conbe made by those skilled inthe art without de- 55 stituting-approximately one half the thickness ofthe apron. The rigidity of the leaf is insured by a channel 23 welded tothe back thereof.

At each end the leaf 2| is bolted or otherwise secured to a hinge strap24 arranged to project upwardly at one side of an arm 25 rigid with thebracket l4. A pin 26 connects each strap and the adjacent arm forpivotal movement. As will be seen by reference to Fig. 2, the pins 26are located so that the pivotal axis of the apron is substantiallycoincident with the upper front edge of the bed plate IS. The upper edgeor bending surface of the leaf 2| accordingly remains at the samedistance from the corner of the bed plate as the apron is rocked aboutits axis. Such rocking is effected in any convenient manner as by a handlever 21.

The type of operation a bending brake is adapted to perform isdetermined to a large extent by the character of the platen installed inthe brake. plated by the present invention is constructed and arrangedwith. a particular view to adapting the brake for the performance of awide Variety of operations, including ordinary bending of either lightor heavy gauge sheets as well as box work,

The improved platen structure contemwithout the necessity ofchanges inthe set-up or adjustment of the brake in changing from one operation tothe other. To this end the platen is constructed to present a fixedbending edge of substantially one half the length of the bed and isequipped with means providing a bending edge of variable lengthextending over the other half of the bed. These bending edges areaccurately alined so that they may be used together or separately as thecharacter of the operation dictates. Thus, it is possible to obtain abending edge of any desired length within the capacity of the brake witha minimum of auxiliary apparatus such as is required for providing thevariable length edge. Initial cost of the brake is therefore reduced andchanges in the set-up for different types of work is facilitated.

In the preferred form illustrated in the drawing, the platen II isconstructed in two sections 3| and 32 suitably joined together inend-to-end relation with the section 32 off-set rearwardly and upwardlywith respect to the section 3|. The sections are desirably of the samelength, each being substantially one half the length of the bed l2. ofrigidity without excessive weight, the sections are preferably ofgenerally triangular cross section. As herein shown, the sections, aresecured together to form a rigid platen structure by bolts 33 insertedthrough a platen 34 welded to the innerend of the section 3| and fianges35 on the adjacent end of the section 32.

The platen structure thus formed is supported in known manner above thebed l2 by slides 38 bolted or otherwise rigidly secured to the outerends of the respective sections, the slides being grooved to receive ahorizontal dovetail way 31 formed on the'adjacent head block I! of theframe. With this arrangement, the platen can be shifted bodily toward orfrom the front of the bed to accommodate sheets of different thickness.The adjustment of the platen structure is effected in the presentinstance by means of an adjusting screw 38 rotatably anchored in a lug39 projecting inwardly from each head block H, the screw threading intothe associated slide 36.

The triangular platen sections are mounted on the slides 36 so thattheir bases lie in planes substantiallyparallel ,to the plane of the bedplate l5'with the apex of the section 3| disposed To obtain amplestrength, and a high degree closely adjacent the front edge of the bedplate. A blade-like member 40 extends along the apex of this section anddefines the fixed bending edge of the platen. Preferably the blademember is removably secured to the platen structure so that it can bereadily removed for repair or replacement when worn or damaged.

Due to the offset relation of the two platensections as hereinbeforeexplained, the apex of the section 32 is disposed above andsubstantially rearwardly of the front edge of the bed plate. Thisprovides space for the mounting of the variable length edge formingmeans which this section of the platen is arranged to support. Thismeans in its preferred form comprises a series of fingers 4| adapted tobe detachably secured to the platen section and to project forwardly anddownwardly therefrom to define a bending edge alined with the bendingedge of the section 3|.

The fingers 4|, as herein shown, are all of the same shape, butpreferably vary progressively in width so that they may be assembled invarious combinations to provide bending edges of different desiredlengths. As will be seen by reference to Fig. 2, each finger comprises agenerally flat body portion 42 having at its front end a downwardly andforwardly projecting foot terminating in a triangular bending edgedefining tip 43. Therear end portion of the body terminates in a hookedtail 44 adapted to engage in an undercut groove 45 in the under side ofthe platen section 32.

For holding the finger firmly in place on the platen, a clamping dog 46is bolted thereto. The dog is arranged to abut at one end against ashoulder 41 upstanding from the surface of the be installed in anydesired combination so as to form, either alone or in conjunction withthe fixed edge provided by the blade 40, a bending edge of any desiredlength from that corresponding to the width of the narrowest finger toone substantially as long as the entire platen. Moreover, the fingers 4|can be spaced away from the .section 3|, if desired, to provide anindependent bending edge of any desired length up to ap proximately onehalf the length of the platen. This is particularly advantageous for boxwork where the accurate adjustment of the length of the bending edgesand the spacing of the fingers provides clearance for flanges previouslyformed on the sheet being operated on.

The fixed bending edge provided by the platen section 3| can, of course,be used alone for plain bending where the width of the sheet does notexceed one half the length of the platen. In fact this section isparticularly suitable for bending metal of heavier gauges than can beformed 1 with the desired degree of accuracy by means of detachablefingers due to their inherent resiliency. Since the bending edge in this'case' is an integral part of the rigid platen. structure, anypossibility of yielding or bending is effectually avoided and sharpaccurate bends. are insured.

[The installation of one or more fingers on the off-set section of theplaten does not interfere in any way with the functioning of the fixedbending edge, hence, the brake can be set up to perform operations ofseveral different types if desired.

The wide variety of operations that can be performed on a brake equippedwith the improved platen herein described, will be readily appreciatedfrom the above remarks. By way of illustration, a number of differentset-ups have been shown diagrammatically in Figs. 3 to 6, inclusive, tomore clearly indicate the range of utility of the brake. Thus, as shownin Fig. 3, the fingers 4| may be detached from the platen and the fixedbending edge provided by the section 3| used alone for bending a metalsheet S of any Width up to one half the width of the bed.

Alternatively, as shown in Fig. 4, a full complement of the fingers 4|may be installed to provide a continuous bending edge of substantiallythe same width as the bed for accommodating a wide metal sheet SIcombination of the fingers 4! may be installed as shown in Fig. 5. Itwill be observed that in this case the innermost finger ll is spacedlaterally away from the platen section 3!. This is to provide clearancefor the fiange F previously formed on the sheet S2. Where the dimensionsof the sheet permit, the flanges F may be formed over the bending edgeof the section 3!, while the final bending operation is performed withthe aid of the fingers assembly on the section 32. Thus, a series of boxforming operations may be carried out with a single setting of thebrake. Such a set-up also leaves the fixed edge accessible at all timesfor bending heavy gauge sheets without disturbing the box bending setupof fingers on the off-set section of the platen. This obviously savestime and labor and materially speeds up production.

Fig. 6 illustrates a set-up for box work involving a sheet S3 ofsomewhat greater width than the fixed edge of the platen section 3|. Forthis purpose the effective length of the fixed bending edge is extendedby the installation of one or more fingers 4| as required. The unusedfingers may be removed or, if desired, they may be shifted to the outerend of the section to provide the necessary clearance for the flange F.

A similar setting may be employed for bending heavy gauge sheets, thatis, the fixed bending edge may be extended by the installation of one ormore fingers 4|. Due to the rigidity of the platen section 3|, thestrain imposed upon the fingers under these conditions is minimized sothat accurate bending of a heavy gauge sheet is permitted.

For box work any It will be observed from the foregoing that theinvention provides an improved platen structure for bending brakes,which materially increases the range of utility of such brakes. Due tothe novel and advantageous construction of the platen, the brake inwhich it is installed is adapted to operate on metal sheets of a widervariety of gauges and to perform numerous operations that haveheretofore been performed on separate machines. This extensive range isattained without complicating the brake structure which is simple andsturdy yet light in weight. Moreover, 1e brake may be readily convertedfor the performance of the various operations with little or no loss oftime and with a minimum of effort.

I claim as my invention:

1. A bending rake having, in combination, an elongated bed, an apronmounted to swing about an axis substantially coincident with the frontedge of the bed, a rigid platen extending longitudinally of said bed andarranged to cooperate therewith to clamp a metal sheet or the like inposition to be bent by the swinging of said apron and to define the lineon which the sheet is bent, said platen having two sections, one sectionpresenting a fixed bending edge extending over a substantial length ofthe platen for direct engagement with the sheet to be bent, the othersection of said platen being offset upwardly and rearwardly from saidone section, said other section being operative to support a series ofdetachable fingers each having a projecting end defining a bending edgeadapted to aline with the bending edge of said one section.

2. In a bending brake having a bed and a swinging apron arranged topivot about an axis substantially coincident with the front edge of thebed, the combination of an elongated rigid platen supported above thebed for movement toward and from the same, said platen comprising twosections each extending substantially one-half the length of the bed,one of said sections presenting a bending edge positioned closelyadjacent the front edge of the bed and adapted for direct engagementwith a metal sheet or the like resting on the bed, the other of saidsections having its front edge disposed above and offset rearwardly fromthe bending edge of said one section and operative to rigidly supportone or more detachable fingers in a forwardly and downwardly projectingposition with the outer ends of the fingers defining a bending edgealined with the bending edge of said one section.

JOHN JENSEN.

